From my own personal experience from wearing the floater suit as well as the bib float pants with the jacket. I would not go with the one piece because of overheating but that's my opinion. I use the Bib pants with a seperate floater coat I use it for ice fishing and for work.
I know everytime I've walked out from shore with a full floater suit on I've been soaked with sweat by the time I get out to a loaction on the ice, and then you have to drill holes, and when you take your arms out of the sleeves and tie them around your waist to get them out of the way there is just too much bulk of clothing to do anything properly.
But ultimately it's going to be whats right for you, I say go to Bass Pro and try some on and walk around the store and see how they feel.
Good Luck and I'm sure some others around here have some good tips.